Miss Flowers did not just want to punish her slave, but she also wanted to humiliate and degrade him. After much thought, she decided to humiliate him using her pee. She pissed into a bowl and she forced him to drink it. And she wanted him to drink it while on all fours like a dog. When he was done, she pissed on his body before she let him go.
Lady Amy and Lady Grace are cruel piss fetishes mistress on their own, but together they are just plain mean. They open up their legs and piss out a funnel full of piss drinking pleasure for their slave. They don't think he is humiliated enough so they spit on him. The mixture of spit and piss fills the mouth of the slave and he is helpless to resist these dominating ladies.